System of railway-signals.



E. C. WOOD.

SYSTEM OF RAILWAY SIGNALS.

' APPLICATION FILED APR. 16. 1909.

1,150,798. Patented Aug. 17, 1915.

3 SHEETS-SHEET l.

COLUMBIA PLANOQRAPH 110., WASHINGTON, D. c,

E. C. WOOD.

SYSTEM OF RAILWAY SIGNALS.

APPLICATION FILED APR. 16. 1909.

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SYSTEM OF RAILWAY $IGNALS.

APPLICATION men APR. 16. 1909.

l 1 50,798. I Patented Aug. 17, 1915.

3 SHEETS-SHEET 3- WITHEEEE'S:

UNTTE TTS i EDWARD C. WVOOID, OF SOMERVILLE, MASSACHUSETTS, ASSIGNOR TO SUBMARINE SIGNAL COHIPANY, 0F WATERVILLE, MAINE, A CORPOB-ATIGN OF MAINE.

SYSTEM OF RAILVVAY-SIGNALS.

Application filed April 16, 1909.

To all whom it may concern:

Be it known that I, EDWARD G. WOOD, o1 Somerville, in the county of Middlesex and State of Massachusetts, a citizen of the United States, have invented a new and useful Improved System of Railway-Signals,

. of which the following is a specification.

The purpose of this invention is to provide an automatic system of electric signaling of such character that the battery or other source of electricity upon which the operation of the system depends may be carried by the locomotive, each locomotive carrying its own source of'electric current. Thus the system is not dependent upon batteries located by the side of the roadbed or in other places where they will be exposed to variations of temperature and other accidents of the weather, but upon batteries which are al ways under supervision.

The problems to be solved by a successful system of signaling presuppose a single track on which trains may run in the same or in opposite directions and from which trains may be directed by switches, and'they are primarily the following :1, the prevention of collision between two trains approaching each other on the same track; 2, the prevention of collision between one train overtaking another, or approaching another which is at a standstill; 3, the prevention of a train from running into an open switch; 4-, the protection of two trains which have been stopped by signal upon the same section of track from trains approaching them in either direction.

7 There are also two other features which it is desirable to provide for'l, the enabling of the flagman togive an automatic signal to an approaching train instead of merely flagging it; 2, thecommunication with a moving or stationary train by telephone, whether it is on the next section or at a distance, and also by telegraph with a train in the same section.

By my system now to be described proision is made for the solution of these various problems and in addi ion the system may embody bells or other s ials and. may

Specification of Letters Patent.

Patented Aug. 17, 1915.

Serial No. 490,378.

be employed for the closing of gates at highway crossings.

For the present I will omit any reference to signals or gates and will confine my description to the locomotive apparatus and the circuits by which it is rendered effective. In the application of my invention shown in the drawings T have used a trolley wire and trolley of ordinary construction, but it will be evident to those skilled in the art that a third rail and shoe may be substituted, these parts being arranged in the ordinary man ner In my description I have used the word conductor to signify the trolley wire or its equivalent.

My invention will be understood byreference to the drawings, in which- Figure 1 showsthe general arrangement of track sections, relays and signal instruments. Fig. 2 shows the relay in detail. Fig. 3 shows diagrammatically the arrangement of circuit closers whereby a head-on collision is prevented. -Fig. 4 shows diagrammatically the arrangement of circuit closers when one train hasstopped voluntarily in a section. Fig. 5 shows diagrammatically the arrangement of circuit closers when one train is overtaking another on the same track. Fig. 6 shows diagrammatically a means for closing a circuit opened by the opening of a switch. Fig. 7 shows a switch circuit closer such as is shown in Fig. 6, and Fig. 8 shows diagrammatically an arrangement of instruments in a locomotive cab.

In the drawings the locomotives or trains are lettered X, Y and Z. Each locomotive as shown in Fig. 1 contains a battery or other source of electrical energy as electrically connected on one side through the axle and wheels :0 with the track G. On the other side it is connected with the signaling instrument m which is connected with the trolley .71 running onthe conductor 1, 2, 3, etc, as the case may be.

The signaling instrument .70 may be of any convenient description such as an ordinary buzzer or a visual signalof which there are many varieties, or it may be of such character as will operate the a1r mechanism to set the air brakes. The peculiar character of this signal forms no part of my present invention and hence I will not describe it further except to say that it should be so constructed and arranged that it will only be operated when the circuit as a whole is one of low resistance, for my invention contemplates the use normally ofa high resistance circuit during the uses of which the signal instrument shall be inoperative, a low resistance circuit being auto- 7 matically substituted for the high resistance i nate it in in descri tion.

circuit as hereinafter described, at which times only the locomotive signal will operate. As for all practical purposes it may be of the; ordinary buzzer type I shall so des- In addition, however, I prefer to use in the locomotive circuit a telegraphic sounder 00 and key 00 (see Fig. 8) by which communication may be established between two trains in the same section of track. Y

My system presupposes the division of the line into sections which may be of any convenient length depending upon the conditionsof the railroad. In the embodiment of my invention shown in the drawings the track is continuous; but the conductor (whether-trolley wire, third rail or otherwise) is divided into sections, and hereafter when I speak of sections of the line I refer to such sections of conductor and the corresponding lengths of track. The ends of these sections are connected by instruments which I shall term relays, each containing a single circuit closer mounted on an armature and operated by electro-magnets. In the drawings the relays are marked A, B, C, D, etc. The conductor entering relay A is marked 1 and for convenience of description that section will be referred to as'the first section. The'conductor connecting relay A 7 and relay B is marked 2, and this section will be called the secondv section. The conductors 3 and 4- connect respectively relays electro-magnets are all alike and I shall describe'only the relay A in detail. I Each 7. electro-magnet at relay A is wound with high resistance coils of fine wire (6, the fine coils on each magnet being connected together and the coils a being connected to the conductor 1 and the coils a? ,with the .conducto-r 2, both being also connected by the branch wires G ,,G and wire A with the track G to form a return. In addition each core is wound withlow resistance coils a aof coarse wire, the (2011s on each magnet being connected,'the coils on magnet A being marked a. and connected with conductor 2, and those on A being marked a .2

series.

jcircuit, because it is so arranged and conand connected with the conductor 1. Between these electro-magnets is hung a circuit closer S pivoted at one end and adapted to be attracted by either electro-magnet to establish at the other end a circuit by closing contacts between one end 9 of the coils (0 and the track wire A through the wire V 7901' between one end g of the coil a and the track wire A through the wire in? according to whichever electromagnet has been energized to attract the circuit closer S Thus the relays being alike, at each relay there is a permanent connection between the end of each conductor which enters the relay and the track or return G, through the high resistance coils of one of the electro magnets and a possible connection with the return through the low resistance coils of the other electro-magnet, this possible connection being completed by the circuit closer which is attracted by one of the electromagnets upon the entrance of a loco-motiven carrying its battery into one'of the conductor sections. There is at each section there fore what may be termed a dead circuit, that is, a metallic circuit ready to be energized electrically by the addition of a battery.

The other relays are identical in character to relay A and the parts thereof are all lettered with exponents indicating their connections, the letters indicating the electromagnets and their parts, however, being those (whether large or small) of their respective relays. Thus the relay B has electro-magnets B B coils 6 6 6 and 6 The circuit closer in each case is marked S with the number of the preceding section in To describe now the operation of this apparatus: Prior to the entrance of-a locomotive carrying a battery upon the cab,the circuit closers lie in their normal neutral positions because there is no battery by which through the locomotive :wheel, axle, etc. Though the colls a are of high resistance,

suff cient current will pass through this circuit to energize the electro-I'nagnetA. and attract the circuit closer S The signaling instrument 9& in'the locomotive,however,, will not be actuated by'such closing of the structed as not to respond tothe current which flows through the circuit when the current passes through the high resistance coils (1. For example, the retractile spring q ofthe armature of a relay which controls the buzzer may be of such strength as to suffer the armature to be attracted and close the local circuit only when the current in the main circuit flows through the low resistance coils. Thus the buzzer will not be responsive to the smaller current flowing through the coils a The'engineer therefore receiving no signal does not stop his train and proceeds into section 2. In crossing from section 1 to section 2 the circuit in section 1 is deadened and the circuit in section 2 is made alive by the transfer of the battery by the locomotive to section 2. There being sufficient track between the two sections to allow the armature to resume its neutral position and afterward to be attracted by the "high resistance coil of the next section when the locomotive has passed over that section. The circuit closer S is now attracted by the electro-magnet A and closes the circuit at b so that the low resistance coils (1 are brought into circuit with conductor 1, and the circuit closer S in relay B is attracted by electro-magnet B so that it closes the circuit at 71, in relay B and hence throws the low resistance coils 6 into circuit with conductor 3. When now a locomotive Y enters the third section (see Fig. 3) the buzzer in its cab immediately sounds because there is a closed circuit of low resistance through the apparatus and battery in locomotive Y, the conductor 3, low resistance coils I), and return G. The engineer therefore will immediately stop his train at the entrance to the third section and await developments. When the locomotive X approaching in the second section enters the third section, its buzzer will sound for the same reason and its engineer will stop. Although the locomotive X has left the second section the circuit closer S in station 13 is not released, being still held by the electro-magnet B energized by the current in the low resistance coils I). There is no current in the high resistance coils Z2 however, as there is no battery on the second section.

At relay C'the original entry of the locomotive Y into the third section has caused the circuit closer S at that relay to be attracted owing to the passage of the current through the high resistance coils c and theirconnections to the track and this sets the circuit closer so that that locomotive and its train is protected from any rear-end collision for the r ason that any locomotive Z enterin section l will find a low resistance circuit through the coils 0 which will energize the buzzer in the locomotive Z when it enters that section. For the same reason the locomotive Z will be protected from rear-end collisions, etc.

By using the telegraphic key and sounder in the locomotives X and Y, telegraphic communication can be established between will be deadencd for a moment.

the two locomotives by which to govern the further action of the trains as below described. In the case above supposed the locomotive X which with locomotive Y is in section 3 will need protection from a train coming up in the rear through the second section. It lacks this protection because the circuit closer S at relay A at the farther end of the section is neutral and the circuit closer S at relay B has been attracted to close the circuit through low resistance coil 6 of section 3. Protection can be secured for locomotive X in either-one. of two ways; first, by making a short circuit in section 2 in any convenient way such as will cut out the high resistance coil 6 so that any locomotive entering section 2 shall find it a circuit of low resistance such that the buzzer in such locomotive will be energized, or second, by the simultaneous opening for an instant of the circuit in locomotives X and Y in section 3 so that the circuit in section 3 This will release the circuit closer S so that it will return to its neutral position and upon the closing of the circuit in one or both locomotives again, the circuit closer S2, which before had been attracted by electro-magnet B will be attracted by B and so throw the low resistance coil 5 into circuit with section 2, thus preparing that section to signal a locomotive entering it from section 1. This action, it will be seen, will not interfere with the protection to the locomotives in section 3 from locomotives in section 4.

In Fig. 4 is shown diagrammatically the situation where locomotive X has come to a standstill in section 3 because of some accident. Being in the section before any locomotive has entered either section 2 or section 1 it has set both circuit closers S and S so as to close the circuit through low resistance coils Z2 and c and hence has protected it from collision at either end. For a locomotive Y entering section 2 or a locomotive Z entering section lfinds a low resistance circuit in each of those sections .which gives the necessary warning to the engineer through the buzzer.

The prevention of a tail-end collision where one train is moving slowly and is followed by a more rapidly moving train is indicated in Fig. 5. Suppose locomotive X has entered section 2, it will throw the circuit closer S at A to the left owing to the circuit established through the coils a and vill throw the circuit closer S at B to the right owing to the circuit through the coils 6 If now a locomotive Y approaches from the-rear from section l on entering section 3 while X is in section Q, it finds the circuit closer S attracted by the electro-magnet B and hence its battery current will pass through the low resistance coil 72 the low resistance coil of electro-magnet B at station 13, and its signal will immediately sound. This appears to provide for the various problems in the operation of a single track road, ora piece of single track, except for the case of an open railroad switch. It being'understood that any form of circuit closerwhich cuts the high resistance out of the circuit, willgive to the signal in the locomotive sutlicient current to operate it, it is only necessary in the case of a switch to provide a short circuit of low resistance between the conductor of the section and the return, whenever the switch is open. Such an arrangement is shown in Fig. 6, where the track is lettered G, the section line being shown for convenience at a third rail and marked 1 a circuit closer adapted for the purpose referred to being shown in Fig. The circuit closer E comprises a push rod 6 mounted in bearings e which form one end forming a low resistance shunt around the high resistance coils in the relays at each end of the section. To protect the push rod from moisture I prefer to connect sleeves of rubber E, E with the .two ends of the bearing 6 and with collars '6 e on the push rod, these sleeves stretching or buckling as occasion may require. Therefore when the railway switch-in any section is opened a direct connection is made between the conductor and return in such section which connection, when a locomotive enters that section causes a circuit to be at once established from the locomotive battery without passing through the high resistance coilsfand thereby the signal in the locomotive is operated, just as happens when the locomotive enters a section when a connectionbetween the conductor of said section and the track has been established through the low resistance coils of the relay by the previous operation of the circuit closer of said relay. I 7

At any time when necessary or other metallic connecting means may be used to establish a direct connection of low resistance between the conductor and track for the purpose of stopping an approaching train by giving a signal in the locomotive when it enters said section. In the case of a third rail a crowbar might be used to make such connection. Such iron rod or crowbar maybe used as a telegraph key by which to signal to a train at a distance in the seean iron rod In addition opportunity is offered by this apparatus whereby one train may communicate with a passenger or other station. Suppose 1t is desirable to communicate from a passenger station with atrain which has been stalled at some distance away in the same section. By connecting the conductor in the section in which the train stands with the return through an ordinary telegraphic apparatus or through a telephone, communication can be established by which directions can either be given to the-train or information secured by which the condition of the train in case of accident may. be learned, it being understood that the locomotive is provided with'similar instruments as above described. It is also possible by locating an ordinary relay in circuit with the conductor of a section to closea circuit through an adjoining crossing signal with its'local battery and so cause such signals to be sounded or set whenever a locomotive with its battery enters that section and thus provides the necessary power. A further advantage of my system is that by the addition of a condenser at each relay the line is given capacity to transmit telephonic communication through a number of sections so that if he desires an engineer :can at any time describe his position and learn the condition of the line. Such condensers are shown at H in Fig. 1, one elementbeing con neeted to the conductor of one section and the other to the conductor of the next section. w

I have described a very simple and desirable embodiment of my invention. It will be perceived that a leading feature of my system is that the locomotive itself carries a battery, and when it enters any given section it brings about such 'an electrical condition in the preceding and following sections that a locomotive thereafter entering one of those sections, being equipped with a similar battery and concomitant apparatus, will .have its signal operated; or, stated in other words, as the locomotive runs, it establishes in each section which it enters a live circuit of high resistance, and thereby establishes in the two adjacent sections dead circuits of low resistance adapted to energize the signal apparatus of any locomotive entering either of such sections." I V have shown and described the normal circuit as of high resistance, and the abnormal or.

r with the next section of the line.

but this arrangement of resistances may be varied under certain conditions.

Specifically-Ihave shown a very simple and eliicient means for thus controlling the condition of the adj acent sections, consisting of what I have called a relay so wound that when energized by a battery, a current will pass through a circuit of high resistance, viz: one including the fine wire coils of the magnet, whereupon the magnet will attract a circuit closer, said circuit closer when attracted to said magnet closing a circuit of low resistance through the coarse wire coils of the same magnet in connection The specific arrangement may be varied in carrying out my invention, but I believe that shown to be the most efiicient and simplest embodiment of my invention. This arrangement of relay will be found useful in some cases where the battery is not carried by the locomotive, and I have drawn some of my claims to cover such use. i

The merits of my system as a whole will be obvious to those skilled in the art, and it is not necessary to enumerate all of them.

Among them I will mention that the bat tery, which is the instrument requiring frequent attention, is situated in the engine itself, which goes to the roundhouse at frequent intervals. The relays which are out on the line, are a simple combination of wound cores and pivoted armature inclosed in a case; these do not deteriorate in ordinary usage as long as they are properly incased, and require no regulation or frequent attention, as does a battery.

The simplicity of the apparatus is apparent. There is no need of dividing the rails of the track into sections, as has been suggested by some previous inventors. The mere addition of the simple relays and a light conductor is all that isnecessary to equipping a line with my system.

It is, of course, preferable to have the signal in the cab of the engine itself, rather than on the side of the road, where it may escape the notice of the engineer; and the objections-to batteries by the roadside are well known. Prior systems, which divided the track into sections and relied on local batteries or polarized bells to give the alarm, have defects and uncertainties in operation which are well recognized in the art. I believe my system to be broadly new, and to attain a degree of efiiciency and certainty of operation which has never been before attained in this art; and I, therefore, desire to claim my system broadly, as well as the specific apparatus by which it is carried out. I have for brevity referred in most passages of the specification and in many of my claims to the source of electrical energy carried by the locomotive as a battery but it will be understood by electricians that some other source of electrical energy, as for instance, a small dynamo, may be employed, and Iintend throughout by the word battery to cover any such equivalent device.

It is evident that I mean to include a locomotive without cars when I use the word train and likewise a handcar might be included within some uses of my invention.

that I claim as my invention is: i

1. In an electric signal system for rai1- ways, a conductor in sections, each section forming a part of a circuit containing no source of electrical current, and adapted at all times to be closed by a locomotive therein, a locomotive carrying a battery and a signal device, means for connecting said battery and signal device in each of said partial circuits, and electrical devices each comprising a single armature and eleotro-magnets having coils of different resistances located between the adjacent sections of the conductor.

2. An electric signal system for railways, comprising a conductor in sections, each sec tion forming a part of a circuit containing no source of electric current, and adapted at all times to be closed by a locomotive therein, a locomotive, a battery carried thereby and means for temporarily connecting said battery with said conductor, and means comprising electro-magnets located at each end of one section operable by the battery current and a circuit closer comprising a single armature operated by either of said electromagnets whereby the resistance of the circuits in the sections adjacent to that occu pied by the battery will be changed and means located in said adjacent sections whereby upon the entrance of locomotives each carrying a battery in said adjacent sections the changed resistance of the circuits thereof will be maintained after said firstnamed locomotive has left said first-named section.

3. An electric signal system for railways comprising in combination, a conductor in sections, each section forming a part of a closed metallic circuit containing no source of electric current, said circuit also including a rail, a battery carried by a locomotive and means for connecting it temporarily with said conductor, and rail, and an electric magnet having a coil of greater resistance constituting a permanent part of said metallic circuit and having also a coil of less resistance, and means operated by said electromagnet for connecting said last named coil in circuit with the adjacent section of the line when said battery energizes the coil of greater resistance.

4. In an electric signal system for railways, a conductor in sections, a locomotive carrying a battery and means for connecting the battery temporarily with said conductor and having signal devices responsive only to an abnormal current, and electrical devices between adjacent sections, each of said electrical devices including an armature and a high resistance coil and a lowresistance coil located on each side of said armature, the high and low resistance coils on each side of the armature being connected with adjacent sectionsof said conductor respectively, the connections of the high resistance coils being permanently closed and those of the low resistance C0llS belng normally,

open but adapted to be closed by the armature when the latter is attracted by the corresponding high resistance coil whereby the presence of a locomotive in one section changes the normal'resistance of the circuit in each adjacent section and maintains it in changed condition after a similar locomotive has entered an adjacent section and said first locomotive has left its section.

5. In an electric signal system ii'or railways, a conductor in sections, a locomotive carrying a battery and signal devices, and means for temporarily connecting said battery with said conductor, and electro-magnets each having coils of high resistance and low resistance between .the sections, said high resistance coils being permanently connected with said sections, said magnets being so wound and arranged that the presence of a locomotive in one section will establish a normal current through the high resistance coils connected to said section and single armatures located between each pair ofsections adapted to be operated bythe high resistance coils connected to such sections to transmit an abnormal current through the signal. devices of an engine entering either adjacent section.

6. In an electric signal system for railways, a track, a conductor divided into sections, a locomotive carrying a battery and means connecting it to said conductor, and electricaldevices between adjacent sections each comprising electro magnets each hav ing coils of high resistance and low resistance and a single armature, said devices being operable by a flow of current in one section to change the resistance of the circuits in the adjacent sections.

7. In an electric signal system for railways, a track, a conductor divided into sections, and permanent electric connections be tween said track and conductor sections including electrical devices between adjacent sections each comprising electro magnets each having coils of high resistance and low resistance and a single armature operable by the flow of an electric current in either section to modify the resistance in the adjacent section.

8. In an electric signal system for railways, a track, a conductor, one of said elements being divided into sections, an electromagnet having a winding permanentlyfconnected with the track and conductor WlllGlll'G- lleves electrical current from the section of line connected therewith and having a low re: 1

sistance winding adapted to be connected with the ad acent section when such current is received and an armature adapted to be attracted by said 'electro emagnet when said electro-magnet is receiving current through its first-named winding and connect said second-named winding with the adjacent section.

9. In an electric signal system for railways, a conductor divided into sections, each section forming part of a circuit normally containing no source of electric current, but" otherwise permanently closed, electro-magnets one located at each end of each section, the electro-magnets of two adjacent sections being located in close proximity, each electro-magnet having high resistance coils in circuit with one section and low resistance coils adapted to be thrown into circuit with the adjacent section, and a single armature common to the adjacent electro-magnets of 7 two sections, whereby said single armature may close the circuit through the low resistance coil of either .electro-magnet.

10. In an electric signal system for railways, a conductor divided into sections, each. section forming part of a circuit normally containing no source of electric current, but otherwise permanently closed, a locomotive carrying a battery and means for connecting it in each of said partial circuits, elec tro-magnets interposed between two'sectionsof the conductor and having high resistance windings connected with said sections, and low resistance windings connectible with such sections, and asingle armature capable of attraction by either of said electro-magnets to close a circuit through one of said low resistance windings.

11. In an electric signal system for rail-- roads, a conductor in sections, a relay be tween two such sections, said relay consisting of a circuit closer and a high'resistance coil and a low resistance coil on each side of said circuit closer, each high resistance coil being permanently connected with a diflerent section, and connections whereby when a high resistance coil connected with one section is energized it attracts the cir-- cuit closer and connects the low resistance coil on that side of the circuit closer with the other section.

12. In an electric signal system for railways, a conductor in sections, a pair of electro-magnets interposed between two sections of the conductor each having coils of greater resistance permanently connected incircuit with a different section of the conductor and each having coilsof less resistance, and means operated by either electro-magnet when its high resistance coils are energized for connecting its low resistance coils with the section connected with the high resistance coils of the other magnet.

13. In an electric signal system for rail ways, a conductor in sections, each section forming part of a circuit normally containing no source of electric current, and adapted at all times to be closed by a locomotive therein, a signal upon a locomotive operated only by an abnormal current, a battery also upon said locomotive and means for connecting said signal and battery with said conductor, a switch, means whereby it is operated by the current from said battery, and means whereby the operation of said switch will change the resistance of the section adjacent to that carrying the switch operating means and place it in condition to operate said signal and maintain it in such condition upon the entry of a locomotive carrying a battery into said adjacent section, said means comprising a low resistance coil connectible by said switch with said adjacent section and adapted thereafter when energized from said adjacent section to hold said switch in its connecting position.

14. In an electric signal system for railways in combination with a locomotive having a source of electrical energy and a signal located thereon, a conductor comprising a series of sections, a track, a series of low resistance connections between said conductor and track, a series of electrically controlled circuit closers, each located between the ends of two sections comprising a single armature adapted to be controlled by current in either section, and means comprising high resistance coils permanently in circuit with said sections respectively whereby the entry of a source of electricity upon one section will cause the circuit closer at each end of said section to be thrown to close the low resistance connection in the next adjoining section, as and for the purposes set forth.

15. In an electric signal system for railways, a conductor comprising a series of sections each having a high resistance coil and a low resistance coil at each end, a signal instrument, a battery, means for temporarily connecting said instrument and battery with said conductor, a return conductor, a series of circuit closers each located between the high resistance coils of two adjacent sections and comprising a single armature adapted to be attracted by either high resistance coil to close the circuit through the low resistance coil of the adjacent section and thereafter to be held in said position by said low resistance coil when it is energized, as set forth.

16. In an electric signal system for railways, a conductor comprising a series of sections, a series of low resistance coils one at each end of a section, a series of circuit closers each comprising a single armature located to close the circuit of one or the other of the adjacent sections through a low resistance coil and to be held by said low resistance coil when said coil is energized, and means operable by a source of electric energy connected with said conductor whereby'upon the entry of said source of electrical energy upon a section the said circuit closers at each end of said section are operated to close the circuits of the adjacent sections through the low resistance coils of such adjacent section,as described.

17. In an electric signal system for rail- Ways, a conductor comprising a series of sections, a series of pairs of electro-magnets, a series of circuit closers located respectively between the electro-magnets of each pair, high resistance and low resistance coils located to energize said electro-magnets, the high resistance coil of the electro-magnet of each pair being permanently connected with a section of said conductor and the low resistance coil of such magnet being connectible by said circuit closer with the adjacent section of said conductor, whereby the said circuit closer being attracted by an electro-magnet energized by current in the high resistance coil connected to one section will close the circuit through the low resistance coil connected to the adjacent section, as and for the purposes set forth.

18. In an electric signal system for railways, a conductor comprising a series of sections, a series of high resistance coils, one connected to each end of each section, and an electro-magnet energized by each coil, a

low resistance coil also adapted to energize said electro-magnet and being normally in open circuit, said electro-magnets being arranged in pairs and the high resistance and low resistance coils of the electro-magnets of each pair being connected to different sections, and a circuit closer located between each pair of electro-magnets and normally neutral, said circuit closers being arranged to close the circuits through said low resistance coils whereby upon the establishment of current in one section the circuit closer at each pair of electro-magnets connected to said section will be attracted by one electro-magnet and close the circuit through the low resistance coil on the same magnet, as set forth.

19. As a means of preventing railroad collisions, a series of closed circuits normally containing no source of electric current, electro-inagnets having high and low resistance coils, said electro-magnets being located one at each end of each circuit and each adapted to be energized by high re nectible to the adjacent circuit, said coils anism being inoperative While in circuit forming part of the same electro-magnet, With said high resistance coils but operableis said armature forming a switch to close the by current in said low resistance coils.

circuit through said loW resistance coil,

whereby such adjacent circuit Will become a I EDWARD WOOD circuit of 10W resistance, a battery carried In presence of V a by a locomotive and a signal mechanismalso R. L. WTLLIAMs,

carried by said locomotive, said signal mech- JOHN FORBES PERKINS. 7

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. i 

